Predicting the reliability is an important task of product life cycle analysis, especially during the product development stages. The uncertainty in the operating conditions and the presence of multistress factors makes this reliability prediction more difficult. In this work, a probabilistic reliability prediction framework is proposed using the linear damage accumulation and degradation modeling for multistress conditions. The multistress-life (S-L) curve for corresponding multistress has been developed using the equivalent stress. The multi S-L model allows extrapolating the expected life product under given operating or test conditions as well as provides input to estimate the reliability as a function of time for both a single multistress factor level and a sequence of multistress-factor levels. The proposed methodology has been demonstrated with newly developed flexible hybrid electronics products.